Battery monitoring apparatus

ABSTRACT

A battery monitoring apparatus is provided for monitoring unit batteries of an assembled battery which are grouped into battery blocks. The battery monitoring apparatus includes a battery ECU, voltage monitors each being mounted to a corresponding one of the battery blocks, and a monitor activation device. The battery ECU is configured to wirelessly transmit commands to the voltage monitors. The voltage monitors are configured to detect voltage information of the unit batteries and wirelessly transmit the detected voltage information to the battery ECU. The monitor activation device is configured to sequentially activate the voltage monitors with time lags in a predetermined order recognized by the battery ECU. Moreover, the battery monitoring apparatus is configured so that: the voltage monitors sequentially start wireless communication with the battery ECU in the predetermined order; and the battery ECU assigns IDs, via the wireless communication, sequentially to the voltage monitors in the predetermined order.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application of InternationalApplication No. PCT/JP2020/002781 filed on Jan. 27, 2020, which is basedon and claims priority from Japanese Patent Application No. 2019-019217filed on Feb. 5, 2019. The entire contents of these applications areincorporated by reference into the present application.

BACKGROUND 1 Technical Field

The present disclosure relates to a battery monitoring apparatus thatmonitors a plurality of unit batteries of an assembled battery installedin a vehicle.

2 Description of Related Art

There is disclosed, for example in Japanese Patent No. JP 5168176 B2, abattery monitoring apparatus for monitoring a plurality of unitbatteries of an assembled battery installed in a vehicle. The unitbatteries of the assembled battery are grouped into a plurality ofbattery blocks. The battery monitoring apparatus includes a battery ECUand a plurality of voltage monitors connected with the battery ECU viacommunication lines. The battery ECU is configured to send commands tothe voltage monitors via the communication lines. Each of the voltagemonitors is mounted to a corresponding one of the battery blocks.Moreover, each of the voltage monitors is configured to detect voltageinformation of the unit batteries of the corresponding battery block andsend the detected voltage information to the battery ECU via thecommunication lines.

SUMMARY

According to the present disclosure, there is provided a batterymonitoring apparatus for monitoring a plurality of unit batteries of anassembled battery installed in a vehicle. The unit batteries of theassembled battery are grouped into a plurality of battery blocks. Thebattery monitoring apparatus includes a battery ECU, a plurality ofvoltage monitors each of which is adapted to be mounted to acorresponding one of the battery blocks, and a monitor activationdevice. The battery ECU is configured to wirelessly transmit commands tothe voltage monitors. The voltage monitors are configured to detectvoltage information of the unit batteries and wirelessly transmit thedetected voltage information to the battery ECU. The monitor activationdevice is configured to sequentially activate the voltage monitors withtime lags therebetween in a predetermined order recognized by thebattery ECU. Moreover, the battery monitoring apparatus is configured sothat: the voltage monitors sequentially start wireless communicationwith the battery ECU in the predetermined order in which the voltagemonitors are sequentially activated by the monitor activation device;and the battery ECU assigns IDs, via the wireless communication,sequentially to the voltage monitors in the predetermined order.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic circuit diagram illustrating the configuration ofa battery monitoring apparatus according to a first embodiment.

FIG. 2 is a flow chart illustrating a process of assigning IDs tovoltage monitors in the battery monitoring apparatus according to thefirst embodiment.

FIG. 3 is a schematic circuit diagram illustrating the configuration ofa battery monitoring apparatus according to a second embodiment.

FIG. 4 is an explanatory diagram illustrating the output voltages ofsignal output ports of a battery ECU in the battery monitoring apparatusaccording to the second embodiment.

FIG. 5 is a flow chart illustrating a process of assigning IDs tovoltage monitors in the battery monitoring apparatus according to thesecond embodiment.

FIG. 6 is a schematic circuit diagram illustrating the configuration ofa battery monitoring apparatus according to a third embodiment.

FIG. 7 is a flow chart illustrating a process of assigning IDs tovoltage monitors in the battery monitoring apparatus according to thethird embodiment.

DESCRIPTION OF EMBODIMENTS

In recent years, there has been a tendency for the amount of electricpower used in vehicles to increase. Accordingly, there has also been atendency for the number of unit batteries included in each of assembledbatteries used in vehicles to increase; thus there has also been atendency for the number of battery blocks, into which the unit batteriesare grouped, and the number of voltage monitors respectivelycorresponding to the battery blocks to increase. Consequently, thenumber of the communication lines connecting the battery ECU and thevoltage monitors is increased. As a countermeasure, it has been proposedto perform wireless communication between the battery ECU and thevoltage monitors.

Moreover, in performing communication between the battery ECU and thevoltage monitors, it is necessary for the battery ECU to identify, foreach of the detected values of voltages sent from the voltage monitors,which one of the battery blocks corresponds to the detected value.Accordingly, it is necessary to assign IDs to the voltage monitors in apredetermined order, for example, in the order in which the electricpotentials of the battery blocks respectively corresponding to thevoltage monitors increase or in the order in which the electricpotentials of the battery blocks respectively corresponding to thevoltage monitors decrease.

In a wired battery monitoring apparatus, it is possible to employ, forexample, a cascade connection in which: all the voltage monitors areconnected in series with each other in the predetermined order viacommunication lines; and the two voltage monitors respectively atopposite ends of the series connection are further connected with thebattery ECU via communication lines. In this case, it is possible toassign IDs to the voltage monitors in the predetermined order byassigning IDs in the order of communication.

However, in a wireless battery monitoring apparatus, it is impossible toemploy the above-described cascade connection. Therefore, it isnecessary to use a different method for assigning IDs to the voltagemonitors in the predetermined order.

The present disclosure has been accomplished in view of the abovecircumstances. With the configuration of the above-described batterymonitoring apparatus according to the present disclosure, it is possiblefor the battery ECU to assign IDs, via the wireless communicationbetween the battery ECU and the voltage monitors, sequentially to thevoltage monitors in the predetermined order that is recognized by thebattery ECU.

Exemplary embodiments will be described hereinafter with reference tothe drawings. It should be noted that for the sake of clarity andunderstanding, identical components having identical functionsthroughout the whole description have been marked, where possible, withthe same reference numerals in the drawings and that for the sake ofavoiding redundancy, descriptions of identical components will not berepeated.

First Embodiment

FIG. 1 illustrates the configuration of a battery monitoring apparatus51 according to the first embodiment. The battery monitoring apparatus51 is configured to be used in a vehicle to monitor an assembled battery60 installed in the vehicle. In addition to the battery monitoringapparatus 51 and the assembled battery 60, there are also installed adrive power apparatus, an auxiliary battery 67 and the like in thevehicle.

The assembled battery 60 has a plurality of unit batteries 63 connectedin series with each other. In the present embodiment, the unit batteries63 of the assembled battery 60 are grouped into a plurality of batteryblocks 62.

The battery monitoring apparatus 51 includes a battery ECU 10 and aplurality of voltage monitors 20. Moreover, the battery monitoringapparatus 51 is also provided with an electric power supply line 31, aplurality of electric power lines 33 and a plurality of detection lines39.

The battery ECU 10 includes an electric power feeding unit 11, an MCU 13and a master unit 16. Moreover, the battery ECU 10 is also provided withan electric power supply port 10 a, a plurality of electric power outputports 10 b 1-10 bN, electrical wiring α and communication wiring β. Inaddition, the master unit 16 includes an antenna 16 b.

Each of the voltage monitors 20 includes a monitoring IC 23 and a slaveunit 26. Moreover, each of the voltage monitors 20 is also provided withan electric power input port 20 a, a plurality of detection ports 20 d,electrical wiring α, communication wiring β and detection wiring δ. Inaddition, the slave unit 26 includes an antenna 26 b.

In the present embodiment, the master unit 16 of the battery ECU 10 andthe slave units 26 of the voltage monitors 20 together constitute awireless communication device.

Next, the configuration of the battery monitoring apparatus 51 accordingto the present embodiment will be described in detail.

The drive power apparatus of the vehicle may be an internal combustionengine, an electric motor or a hybrid power apparatus consisting of aninternal combustion engine and an electric motor.

Each of the unit batteries 63 of the assembled battery 60 may be asingle battery cell or a collection of battery cells connected in serieswith each other. In the present embodiment, each battery cell isimplemented by a lithium cell. However, it should be noted that eachbattery cell may be implemented by any other cell.

Each of the voltage monitors 20 is mounted to a corresponding one of thebattery blocks 62.

The auxiliary battery 67 is connected, via the electric power supplyline 31, with the electric power supply port 10 a of the battery ECU 10.The electric power feeding unit 11 is connected, via the electricalwiring α, with the electric power supply port 10 a, the MCU 13 and themaster unit 16.

The electric power feeding unit 11 includes an electric power feedingswitch (not shown). When a power switch (i.e., a start switch of thedrive power apparatus) of the vehicle is turned on, the electric powerfeeding switch of the electric power feeding unit 11 is also turned onin conjunction with the power switch. Moreover, when the power switch ofthe vehicle is turned off, the electric power feeding switch of theelectric power feeding unit 11 is also turned off in conjunction withthe power switch. Furthermore, when the electric power feeding switch isin an off-state, electric power is fed by the electric power feedingunit 11 neither to the MCU 13 nor to the master unit 16. On the otherhand, upon the electric power feeding switch being turned on, electricpower supplied from the auxiliary battery 67 is fed by the electricpower feeding unit 11 to both the MCU 13 and the master unit 16;consequently, the battery ECU 10 is activated.

The MCU 13 issues commands to the monitoring ICs 23 of the voltagemonitors 20. The commands include a command to acquire voltageinformation of the unit batteries 63 and a command to discharge the unitbatteries 63.

More specifically, the MCU 13 and the master unit 16 are communicablyconnected with each other via the communication wiring (3. The MCU 13sends the commands and the like to the master unit 16 via thecommunication wiring (3. On the other hand, the master unit 16 sends thevoltage information and the like, which are wirelessly received from theslave units 26 of the voltage monitors 20, to the MCU 13 via thecommunication wiring (3.

In the present embodiment, the battery ECU 10 (more specifically, theMCU 13 of the battery ECU 10) constitutes a monitor activation devicethat sequentially activates the voltage monitors 20 with time lagstherebetween (i.e., respectively at different times). The MCU 13 isconnected, via the electrical wiring α, with each of the electric poweroutput ports 10 b 1-10 bN.

The electric power output ports 10 b 1-10 bN of the battery ECU 10 arerespectively connected with the electric power input ports 20 a of thevoltage monitors 20 via the electric power lines 33. Specifically, thefirst electric power output port 10 b 1 is connected with the electricpower input port 20 a of the voltage monitor 20 corresponding to thebattery block 62 having the lowest electric potential. Moreover, thesecond electric power output port 10 b 2 is connected with the electricpower input port 20 a of the voltage monitor 20 corresponding to thebattery block 62 having the second lowest electric potential. In thismanner, the electric power output ports 10 b 1-10 bN of the battery ECU10 are sequentially connected with the corresponding electric powerinput ports 20 a of the voltage monitors 20 in the order in which theelectric potentials of the battery blocks 62 respectively correspondingto the voltage monitors 20 increase. Furthermore, the MCU 13sequentially starts, in the order in which the electric potentials ofthe battery blocks 62 respectively corresponding to the voltage monitors20 increase, electric power supply to the voltage monitors 20 via theelectric power output ports 10 b 1-10 bN of the battery ECU 10, theelectric power lines 33 and the electric power input ports 20 a of thevoltage monitors 20. Consequently, the voltage monitors 20 aresequentially activated in the order in which the electric potentials ofthe battery blocks 62 respectively corresponding to the voltage monitors20 increase. Moreover, the master unit 16 of the battery ECU 10recognizes the voltage monitors 20 as being sequentially activated inthe order in which the electric potentials of the battery blocks 62respectively corresponding to the voltage monitors 20 increase.

In each of the voltage monitors 20, the electric power input port 20 ais connected, via the electrical wiring α, with both the monitoring IC23 and the slave unit 26. Therefore, upon supply of electric power tothe electric power input port 20 a, electric power is further suppliedto both the monitoring IC 23 and the slave unit 26, thereby activatingthe voltage monitor 20.

Moreover, in each of the voltage monitors 20, the monitoring IC 23includes a multiplexer. The multiplexer is connected, via the detectionwiring δ, with each of the detection ports 20 d. Further, two of thedetection ports 20 d are respectively connected with opposite ends ofthe corresponding battery block 62 via the corresponding detection lines39; the remaining detection ports 20 d are respectively connected withjunction points between terminals of the unit batteries 63 of thecorresponding battery block 62 via the corresponding detection lines 39.The multiplexer is configured to sequentially detect the voltageinformation between the terminals of each of the unit batteries 63. Thevoltage information may be the actual voltage between the terminals ofeach of the unit batteries 63; alternatively, it may be information onother parameters from which the actual voltage can be derived, such aselectric current flowing through a predetermined part. Moreover, themultiplexer is further configured to discharge any of the unit batteries63 as needed. Consequently, it is possible to perform a balancingprocess for equalizing the SOCs (or states of charges) of the unitbatteries 63.

Furthermore, in each of the voltage monitors 20, the monitoring IC 23and the slave unit 26 are communicably connected with each other via thecommunication wiring β. The slave unit 26 sends the commands and thelike, which are wirelessly received from the master unit 16 of thebattery ECU 10, to the monitoring IC 23 via the communication wiring β.On the other hand, the monitoring IC 23 sends the voltage informationand the like to the slave unit 26 via the communication wiring β.

Upon establishment of a wireless communication link between the masterunit 16 of the battery ECU 10 and each of the slave units 26 of thevoltage monitors 20, the commands issued by the MCU 13 of the batteryECU 10 are wirelessly transmitted by the master unit 16 to the slaveunits 26; the voltage information is wirelessly transmitted by the slaveunits 26 to the master unit 16.

Next, with reference to FIG. 2, explanation will be given of a processof assigning IDs to the voltage monitors 20 in the battery monitoringapparatus 51 according to the present embodiment.

In step S101, the battery ECU 10 is activated upon the power switch ofthe vehicle being turned on.

In step S102, the battery ECU 10 starts supplying electric power to, ofthe voltage monitors 20 having not been activated yet, the voltagemonitor 20 corresponding to the battery block 62 having the lowestelectric potential via the corresponding electric power line 33.Consequently, in step S103, the voltage monitor 20 is activated.

In step S104, the slave unit 26 of the voltage monitor 20 wirelesslycommunicates with the master unit 16 of the battery ECU 10 to establisha communication link therebetween.

In step S105, the master unit 16 assigns, of the IDs having not beenassigned yet, the lowest ID to the slave unit 26 that has justestablished the communication link with the master unit 16.

In step S106, the MCU 13 of the battery ECU 10 determines whether thereis at least one voltage monitor 20 having not been activated yet.

If the determination in step S106 results in a “YES” answer, i.e., ifthere is at least one voltage monitor 20 having not been activated yet,the process returns to step S102 to repeat steps S102-S106.

In contrast, if the determination in step S106 results in a “NO” answer,i.e., if all the voltage monitors 20 have been activated, the processproceeds to step S107.

In step S107, the process of assigning IDs to the voltage monitors 20 isterminated.

More particularly, in the present embodiment, the supply of electricpower to the voltage monitor 20 corresponding to the battery block 62having the lowest electric potential is started in step S102 by startingthe supply of electric power to that one of the electric power outputports 10 b 1-10 bN which is connected with the voltage monitor 20 viathe corresponding electric power line 33. Moreover, the determination asto whether there is at least one voltage monitor 20 having not beenactivated yet is made in step S106 by determining whether there is, ofthe electric power output ports 10 b 1-10 bN, at least one electricpower output port having not been supplied with electric power yet.

As described above, in the ID assignment process according to thepresent embodiment, the slave unit 26 of the activated voltage monitor20 wirelessly communicates with the master unit 16 of the battery ECU 10to establish a communication link therebetween (steps S102-S104). Then,an ID is assigned to the slave unit 26 by the master unit 16 (stepS105). Thereafter, the next voltage monitor 20 is supplied with electricpower from the battery ECU 10 (step S102) and thereby activated (stepS103).

According to the present embodiment, it is possible to achieve thefollowing advantageous effects.

As described above, in the present embodiment, the battery monitoringapparatus 51 is configured to monitor the unit batteries 63 of theassembled battery 60 installed in a vehicle. The unit batteries 63 ofthe assembled battery 60 are grouped into the plurality of batteryblocks 62. The battery monitoring apparatus 51 includes the battery ECU10, the voltage monitors 20 and the monitor activation device that isconstituted of the battery ECU 10 in the present embodiment. The batteryECU 10 is configured to wirelessly transmit commands to the voltagemonitors 20. Each of the voltage monitors 20 is mounted to acorresponding one of the battery blocks 62. The voltage monitors 20 areconfigured to detect voltage information of the unit batteries 63 andwirelessly transmit the detected voltage information to the battery ECU10. The monitor activation device (more particularly, the battery ECU 10in the present embodiment) is configured to sequentially activate thevoltage monitors 20 with time lags therebetween in a predetermined orderrecognized by the battery ECU 10. Moreover, the battery monitoringapparatus 51 is configured so that: the voltage monitors 20 sequentiallystart wireless communication with the battery ECU 10 in thepredetermined order in which the voltage monitors 20 are sequentiallyactivated by the monitor activation device; and the battery ECU 10assigns IDs, via the wireless communication, sequentially to the voltagemonitors 20 in the predetermined order.

With the above configuration, it becomes possible for the battery ECU 10to assign IDs, via the wireless communication between the battery ECU 10and the voltage monitors 20, sequentially to the voltage monitors 20 inthe predetermined order that is recognized by the battery ECU 10.

Moreover, in the present embodiment, all the battery blocks 62 areconnected in series with each other. The predetermined order, in whichthe voltage monitors 20 are sequentially activated, is the order inwhich the electric potentials of the battery blocks 62 respectivelycorresponding to the voltage monitors 20 increase. Consequently, itbecomes possible for the battery ECU 10 to easily and reliably performthe assignment of IDs to the voltage monitors 20.

In the present embodiment, the monitor activation device is constitutedof the battery ECU 10. Each of the voltage monitors 20 is connected withthe battery ECU 10 via a corresponding one of the electric power lines33. Each of the voltage monitors 20 is configured to be supplied withelectric power from the battery ECU 10 via the corresponding electricpower line 33 and thereby activated. The battery ECU 10 is configured tosequentially start the supply of electric power to the voltage monitors20 in the predetermined order (more particularly, in the order in whichthe electric potentials of the battery blocks 62 respectivelycorresponding to the voltage monitors 20 increase in the presentembodiment) and thereby sequentially activate the voltage monitors 20 inthe predetermined order. Consequently, it becomes possible for thebattery ECU 10 to easily and reliably perform the assignment of IDs tothe voltage monitors 20 by sequentially supplying electric power to thevoltage monitors 20.

Second Embodiment

A battery monitoring apparatus 52 according to the second embodiment hasa similar configuration to the battery monitoring apparatus 51 accordingto the first embodiment. Therefore, the differences of the batterymonitoring apparatus 52 from the battery monitoring apparatus 51 will bemainly described hereinafter.

FIG. 3 illustrates the configuration of the battery monitoring apparatus52 according to the second embodiment.

As shown in FIG. 3, in the present embodiment, the battery monitoringapparatus 52 includes a plurality of signal lines 35 and a plurality ofelectric power supply lines 38 instead of the electric power lines 33described in the first embodiment.

Moreover, in the present embodiment, the battery ECU 10 is provided witha plurality of signal output ports 10 c 1-10 cN instead of the electricpower output ports 10 b 1-10 bN described in the first embodiment.Further, in the present embodiment, the battery ECU 10 is provided withsignal wiring γ instead of part of the electrical wiring α described inthe first embodiment.

Furthermore, in the present embodiment, each of the voltage monitors 20is provided with an electric power supply port 20A and a signal inputport 20 b instead of the electric power input port 20 a described in thefirst embodiment. Further, the voltage monitor 20 is also provided withan electric power feeding unit 21.

Next, the configuration of the battery monitoring apparatus 52 accordingto the present embodiment will be described in detail.

The signal wiring γ and the signal lines 35 are formed of electricalconductor wires. The signal wiring γ and the signal lines 35 transmit anactivation signal, but neither commands nor voltage values.

The MCU 13 is connected, via the signal wiring γ, with each of thesignal output ports 10 c 1-10 cN.

The signal output ports 10 c 1-10 cN of the battery ECU 10 arerespectively connected with the signal input ports 20 b of the voltagemonitors 20 via the signal lines 35. Specifically, the first signaloutput port 10 c 1 is connected with the signal input port 20 b of thevoltage monitor 20 corresponding to the battery block 62 having thelowest electric potential. Moreover, the second signal output port 10 c2 is connected with the signal input port 20 b of the voltage monitor 20corresponding to the battery block 62 having the second lowest electricpotential. In this manner, the signal output ports 10 c 1-10 cN of thebattery ECU 10 are sequentially connected with the corresponding signalinput ports 20 b of the voltage monitors 20 in the order in which theelectric potentials of the battery blocks 62 respectively correspondingto the voltage monitors 20 increase. Furthermore, via the signal outputports 10 c 1-10 cN of the battery ECU 10, the signal lines 35 and thesignal input ports 20 b of the voltage monitors 20, the MCU 13 sends theactivation signal sequentially to the voltage monitors 20 in the orderin which the electric potentials of the battery blocks 62 respectivelycorresponding to the voltage monitors 20 increase.

In each of the voltage monitors 20, the electric power feeding unit 21is connected, via the signal wiring γ, with the signal input port 20 b.Moreover, the electric power feeding unit 21 is connected, via theelectrical wiring α, with the electric power supply port 20A. Further,the electric power supply port 20A is connected, via a corresponding oneof the electric power supply lines 38, with the assembled battery 60.

The electric power feeding unit 21 includes an electric power feedingswitch (not shown). Without receipt of the activation signal, theelectric power feeding switch is kept in an off-state. Upon receipt ofthe activation signal, the electric power feeding switch is turned on.When the electric power feeding switch is in the off-state, electricpower is fed by the electric power feeding unit 21 neither to themonitoring IC 23 nor to the slave unit 26. On the other hand, upon theelectric power feeding switch being turned on, electric power suppliedfrom the unit batteries 63 is fed by the electric power feeding unit 21to both the monitoring IC 23 and the slave unit 26; consequently, thevoltage monitor 20 is activated. More specifically, the electric powerfeeding unit 21 is supplied with electric power from the unit batteries63 of the battery block 62 corresponding to the voltage monitor 20 thatincludes the electric power feeding unit 21.

FIG. 4 illustrates the output voltages of the signal output ports 10 c1-10 cN of the battery ECU 10. As can be seen from FIG. 4, the outputvoltages of the signal output ports 10 c 1-10 cN are changed from alower voltage Lo to a higher voltage Hi sequentially with time lagstherebetween (i.e., respectively at different times) from the lowestone, i.e., in the order of the first signal output port 10 c 1, thesecond signal output port 10 c 2, . . . , and the Nth signal output port10 cN. The higher voltage Hi serves as the activation signal.

Next, with reference to FIG. 5, explanation will be given of a processof assigning IDs to the voltage monitors 20 in the battery monitoringapparatus 52 according to the present embodiment.

In step S201, the battery ECU 10 is activated upon the power switch ofthe vehicle being turned on.

In step S202, the battery ECU 10 sends the activation signal to, of thevoltage monitors 20 having not been activated yet, the voltage monitor20 corresponding to the battery block 62 having the lowest electricpotential via the corresponding signal line 35. Consequently, in stepS203, the voltage monitor 20 is activated.

In step S204, the slave unit 26 of the voltage monitor 20 wirelesslycommunicates with the master unit 16 of the battery ECU 10 to establisha communication link therebetween.

In step S205, the master unit 16 assigns, of the IDs having not beenassigned yet, the lowest ID to the slave unit 26 that has justestablished the communication link with the master unit 16.

In step S206, the MCU 13 of the battery ECU 10 determines whether thereis at least one voltage monitor 20 having not been activated yet.

If the determination in step S206 results in a “YES” answer, i.e., ifthere is at least one voltage monitor 20 having not been activated yet,the process returns to step S202 to repeat steps S202-S206.

In contrast, if the determination in step S206 results in a “NO” answer,i.e., if all the voltage monitors 20 have been activated, the processproceeds to step S207.

In step S207, the process of assigning IDs to the voltage monitors 20 isterminated.

More particularly, in the present embodiment, the sending of theactivation signal to the voltage monitor 20 corresponding to the batteryblock 62 having the lowest electric potential is performed in step S202by changing the output voltage of that one of the signal output ports 10c 1-10 cN which is connected with the voltage monitor 20 via thecorresponding signal line 35 from the lower voltage Lo to the highervoltage Hi. Moreover, the determination as to whether there is at leastone voltage monitor 20 having not been activated yet is made in stepS206 by determining whether there is, of the signal output ports 10 c1-10 cN, at least one signal output port whose output voltage is equalto the lower voltage Lo.

As described above, in the ID assignment process according to thepresent embodiment, the slave unit 26 of the activated voltage monitor20 wirelessly communicates with the master unit 16 of the battery ECU 10to establish a communication link therebetween (steps S202-S204). Then,an ID is assigned to the slave unit 26 by the master unit 16 (stepS205). Thereafter, the activation signal is sent from the battery ECU 10to the next voltage monitor 20 (step S202), thereby activating the nextvoltage monitor 20 (step S203).

According to the present embodiment, it is possible to achieve the sameadvantageous effects as described in the first embodiment.

That is, with the configuration of the battery monitoring apparatus 52according to the present embodiment, it is also possible for the batteryECU 10 to assign IDs, via wireless communication between the battery ECU10 and the voltage monitors 20, sequentially to the voltage monitors 20in a predetermined order recognized by the battery ECU 10 (moreparticularly, in the order in which the electric potentials of thebattery blocks 62 respectively corresponding to the voltage monitors 20increase in the present embodiment).

Moreover, in the present embodiment, to sequentially activate thevoltage monitors 20, the battery ECU 10 sends the activation signalsequentially to the voltage monitors 20 via the corresponding signallines 35, instead of supplying electric power sequentially to thevoltage monitors 20 via the corresponding electric power lines 33 as inthe first embodiment. The signal lines 5 are allowed to be higher inelectrical resistance than the electric power lines 33; therefore, thesignal line 35 can be made thinner than the electric power lines 33.Moreover, the signal lines 35 transmit the activation signal (moreparticularly, the higher voltage Hi in the present embodiment), butneither commands nor voltage values; therefore, the signal lines 35 canbe formed of simple electrical conductor wires. Consequently, it becomespossible to simplify the wiring between the battery ECU 10 and thevoltage monitors 20 in comparison with the case of connecting thebattery ECU 10 and the voltage monitors 20 via general communicationlines.

Furthermore, in the present embodiment, since the battery ECU 10 doesnot supply electric power to the voltage monitors 20, it is unnecessaryto provide in the battery ECU 10 any electric power supply circuit forsupplying electric power to the voltage monitors 20. Consequently, itbecomes possible to suppress the circuit scale of the battery ECU 10.

In addition, in the present embodiment, the voltage monitors 20 aresupplied with electric power from the unit batteries 63 that are themonitoring targets of the voltage monitors 20. Consequently, it becomespossible to secure the required electric power for the voltage monitors20 with a simple configuration.

Third Embodiment

A battery monitoring apparatus 53 according to the third embodiment hasa similar configuration to the battery monitoring apparatus 52 accordingto the second embodiment. Therefore, the differences of the batterymonitoring apparatus 53 from the battery monitoring apparatus 52 will bemainly described hereinafter.

FIG. 6 illustrates the configuration of the battery monitoring apparatus53 according to the third embodiment.

As shown in FIG. 6, in the present embodiment, the battery monitoringapparatus 53 includes a single signal line 35 and a plurality ofconnection lines 36 instead of the plurality of signal lines 35described in the second embodiment.

Moreover, in the present embodiment, the battery ECU 10 is provided witha single signal output port 10 c instead of the plurality of signaloutput ports 10 c 1-10 cN described in the second embodiment.

Furthermore, in the present embodiment, each of the voltage monitors 20is further provided with a signal output port 20 c.

Next, the configuration of the battery monitoring apparatus 53 accordingto the present embodiment will be described in detail.

The signal output port 10 c of the battery ECU 10 is connected, via thesignal line 35, with the signal input port 20 b of the voltage monitor20 corresponding to the battery block 62 having the lowest electricpotential (i.e., a predetermined one of the voltage monitors 20).

In each of the voltage monitors 20, the slave unit 26 is connected, viathe signal wiring γ, with the signal output port 20 c. Moreover, thesignal output port 20 c is connected, via a corresponding one of theconnection lines 36, with the signal input port 20 b of another of thevoltage monitors 20 which corresponds to the battery block 62 connectedwith and higher in electric potential than the battery block 62corresponding to the voltage monitor 20. Consequently, all the voltagemonitors 20 are connected in series with each other via the connectionlines 36.

The connection lines 36 are formed of electrical conductor wires. Inaddition, the electric conductor wires forming the connection lines 36may be of the same type as or a different type from the electricconductor wire of which the signal line 35 is formed.

In the present embodiment, the battery ECU 10 (more specifically, theMCU 13 of the battery ECU 10) and the voltage monitors 20 (morespecifically, the slave units 26 of the voltage monitors 20) togetherconstitute a monitor activation device that sequentially activates thevoltage monitors 20 with time lags therebetween (i.e., respectively atdifferent times).

Next, with reference to FIG. 7, explanation will be given of a processof assigning IDs to the voltage monitors 20 in the battery monitoringapparatus 53 according to the present embodiment.

In step S301, the battery ECU 10 is activated upon the power switch ofthe vehicle being turned on.

In step S302, the battery ECU 10 sends the activation signal, via thesignal line 35, to the voltage monitor 20 that is connected with thebattery ECU 10 via the signal line 35. Consequently, in step S303, thevoltage monitor 20 corresponding to the battery block 62 having thelowest electric potential is activated.

In step S304, the slave unit 26 of the voltage monitor 20 wirelesslycommunicates with the master unit 16 of the battery ECU 10 to establisha communication link therebetween.

In step S305, the master unit 16 assigns, of the IDs having not beenassigned yet, the lowest ID to the slave unit 26 that has justestablished the communication link with the master unit 16.

In step S306, if there is a voltage monitor 20 one-level higher than thevoltage monitor 20 that includes the slave unit 26 to which an ID hasjust been assigned, then the slave unit 26 sends, via the correspondingconnection line 36, the activation signal to the one-level highervoltage monitor 20. Consequently, in step S307, the one-level highervoltage monitor 20 is activated. Then, the slave unit 26 of theactivated voltage monitor 20, to which no ID has been assigned yet,transmits a wireless signal to the master unit 16 of the battery ECU 10.

In step S308, the master unit 16 of the battery ECU 10 determineswhether there is a wireless signal received from a slave unit 26 havingno ID.

If the determination in step S308 results in a “YES” answer, i.e., ifthere is a wireless signal received by the master unit 16 from a slaveunit 26 having no ID, the process returns to step S304 in which themaster unit 16 wirelessly communicates with the slave unit 26 having noID to establish a communication link therebetween. Thereafter, stepsS305-S308 are repeated.

In contrast, if the determination in step S308 results in a “NO” answer,i.e., if there is no wireless signal received by the master unit 16 froma slave unit 26 having no ID, the process proceeds to step S309.

In step S309, the process of assigning IDs to the voltage monitors 20 isterminated.

More particularly, in the present embodiment, the sending of theactivation signal, if there is a voltage monitor 20 one-level higherthan the activated voltage monitor 20, to the one-level higher voltagemonitor 20 is performed in step S306 by the slave unit 26 of theactivated voltage monitor 20 by sending the activation signal to thesignal output port 20 c of the activated voltage monitor 20.Consequently, if there is a connection line 36 connected with the signaloutput port 20 c of the activated voltage monitor 20, i.e., if there isa voltage monitor 20 one-level higher than the activated voltage monitor20, the activation signal will be sent to the one-level higher voltagemonitor 20. In contrast, if there is no connection line 36 connectedwith the signal output port 20 c of the activated voltage monitor 20,i.e., if there is no voltage monitor 20 one-level higher than theactivated voltage monitor 20, the activation signal will not be sent toany other voltage monitors 20.

As described above, in the ID assignment process according to thepresent embodiment, the slave unit 26 of the activated voltage monitor20 wirelessly communicates with the master unit 16 of the battery ECU 10to establish a communication link therebetween (steps S302-S304). Then,an ID is assigned to the slave unit 26 by the master unit 16 (stepS305). Thereafter, the activation signal is sent from the activatedvoltage monitor 20 to the one-level higher voltage monitor 20 (stepS306), thereby activating the one-level higher voltage monitor 20 (stepS307).

According to the present embodiment, it is possible to achieve the sameadvantageous effects as described in the second embodiment.

Moreover, in the present embodiment, each adjacent pair of the voltagemonitors 20 is connected via a corresponding one of the connection lines36; therefore, the battery ECU 10 is only required to be connected witha predetermined one of the voltage monitors 20. Consequently, it becomespossible to simplify the wiring between the battery ECU 10 and thevoltage monitors 20 in comparison with the case of connecting each ofthe voltage monitors 20 with the battery ECU 10 via a corresponding oneof the signal lines 35 as in the second embodiment.

Furthermore, in the present embodiment, all the voltage monitors 20 areconnected in series with each other via the connection lines 36;therefore, even with increase in the number of the voltage monitors 20,it is sufficient for the battery ECU 10 to include only one signaloutput port 10 c to which the signal line 35 is connected. Consequently,it becomes possible to cope with increase in the number of the voltagemonitors 20 without providing any additional signal output ports in thebattery ECU 10.

Other Embodiments

The above-described embodiments may be modified as follows.

In the above-described embodiments, all the battery blocks 62 areconnected in series with each other. Moreover, the predetermined order,in which the voltage monitors 20 are sequentially activated and IDs aresequentially assigned to the voltage monitors 20, is the order in whichthe electric potentials of the battery blocks 62 respectivelycorresponding to the voltage monitors 20 increase. As an alternative,the predetermined order may be the order in which the electricpotentials of the battery blocks 62 respectively corresponding to thevoltage monitors 20 decrease. As another alternative, all the batteryblocks 62 may be connected in parallel with each other; thepredetermined order may be the order from the voltage monitor 20corresponding to the battery block 62 arranged at one end of theparallel connection to the voltage monitor 20 corresponding to thebattery block 62 arranged at the other end of the parallel connection.

In the first embodiment, the battery ECU 10 may alternatively beconfigured so that: electric power is directly supplied from theelectric power feeding unit 11 to the electric power output ports 10 b1-10 bN; and the MCU 13 controls the on/off state of the electric powersupply (in other words, selectively permits and interrupts the electricpower supply).

In the above-described embodiments, the monitor activation function ofthe MCU 13 of the battery ECU 10 may alternatively be performed by adevice provided outside the battery ECU 10.

In the second and third embodiments, the electric power feeding units 21of the voltage monitors 20 may alternatively be supplied with electricpower from an electric power source other than the unit batteries 63 ofthe corresponding battery blocks 62, such as the auxiliary battery 67.

While the present disclosure has been described pursuant to theexemplary embodiments, it should be appreciated that the presentdisclosure is not limited to the exemplary embodiments. Instead, thepresent disclosure encompasses various modifications and changes withinequivalent ranges. In addition, various combinations and modes are alsoincluded in the category and the scope of technical idea of the presentdisclosure.

What is claimed is:
 1. A battery monitoring apparatus for monitoring aplurality of unit batteries of an assembled battery installed in avehicle, the unit batteries of the assembled battery being grouped intoa plurality of battery blocks, the battery monitoring apparatuscomprising: a battery ECU; a plurality of voltage monitors each of whichis adapted to be mounted to a corresponding one of the battery blocks;and a monitor activation device, wherein the battery ECU is configuredto wirelessly transmit commands to the voltage monitors, the voltagemonitors are configured to detect voltage information of the unitbatteries and wirelessly transmit the detected voltage information tothe battery ECU, and the monitor activation device is configured tosequentially activate the voltage monitors with time lags therebetweenin a predetermined order recognized by the battery ECU, wherein thebattery monitoring apparatus is configured so that: the voltage monitorssequentially start wireless communication with the battery ECU in thepredetermined order in which the voltage monitors are sequentiallyactivated by the monitor activation device; and the battery ECU assignsIDs, via the wireless communication, sequentially to the voltagemonitors in the predetermined order.
 2. The battery monitoring apparatusas set forth in claim 1, wherein all the battery blocks are connected inseries with each other, and the predetermined order, in which thevoltage monitors are sequentially activated by the monitor activationdevice, is an order in which electric potentials of the battery blocksrespectively corresponding to the voltage monitors decrease or an orderin which the electric potentials of the battery blocks respectivelycorresponding to the voltage monitors increase.
 3. The batterymonitoring apparatus as set forth in claim 1, wherein the voltagemonitors are further configured to be sequentially activated in thepredetermined order in response to electric power sequentially suppliedto the voltage monitors in the predetermined order or signalssequentially transmitted to the voltage monitors in the predeterminedorder.
 4. The battery monitoring apparatus as set forth in claim 3,wherein the monitor activation device comprises the battery ECU, andeach of the voltage monitors is connected with the battery ECU viapredetermined wiring.
 5. The battery monitoring apparatus as set forthin claim 1, wherein the monitor activation device comprises the batteryECU, each of the voltage monitors is connected with the battery ECU viaa corresponding one of a plurality of electric power lines, each of thevoltage monitors is configured to be supplied with electric power fromthe battery ECU via the corresponding electric power line and therebyactivated, and the battery ECU is configured to sequentially start thesupply of electric power to the voltage monitors in the predeterminedorder and thereby sequentially activate the voltage monitors in thepredetermined order.
 6. The battery monitoring apparatus as set forth inclaim 1, wherein the monitor activation device comprises the batteryECU, each of the voltage monitors is configured to be activated, uponreceipt of a predetermined activation signal, using electric powersupplied from an electric power source other than the battery ECU, eachof the voltage monitors is connected with the battery ECU via acorresponding one of a plurality of signal lines that transmit theactivation signal, but neither the commands nor the voltage information,and the battery ECU is configured to send the activation signal, via thecorresponding signal lines, sequentially to the voltage monitors in thepredetermined order and thereby sequentially activate the voltagemonitors in the predetermined order.
 7. The battery monitoring apparatusas set forth in claim 6, wherein for each of the voltage monitors, theelectric power source other than the battery ECU is the unit batteriesof the battery block corresponding to the voltage monitor.
 8. Thebattery monitoring apparatus as set forth in claim 1, wherein themonitor activation device comprises the battery ECU and the voltagemonitors, each of the voltage monitors is configured to be activated,upon receipt of a predetermined activation signal, using electric powersupplied from an electric power source other than the battery ECU, thebattery ECU is connected with a predetermined one of the voltagemonitors via a signal line that transmits the activation signal, butneither the commands nor the voltage information, all the voltagemonitors are connected, via a plurality of connection lines thattransmit the activation signal, in series with each other in thepredetermined order from the predetermined voltage monitor, and thebattery monitoring apparatus is configured so that: the battery ECUsends the activation signal to the predetermined voltage monitor via thesignal line and thereby activates the predetermined voltage monitor; andthen the remaining voltage monitors are sequentially activated in thepredetermined order through successive transmission of the activationsignal from each activated one of the voltage monitors to another of thevoltage monitors which is connected with the activated voltage monitorvia a corresponding one of the connection lines and has not beenactivated yet.
 9. The battery monitoring apparatus as set forth in claim8, wherein for each of the voltage monitors, the electric power sourceother than the battery ECU is the unit batteries of the battery blockcorresponding to the voltage monitor.
 10. A battery monitoring apparatusfor monitoring a plurality of unit batteries of an assembled batteryinstalled in a vehicle, the unit batteries of the assembled batterybeing grouped into a plurality of battery blocks, the battery monitoringapparatus comprising: a battery ECU; a plurality of voltage monitorseach of which is adapted to be mounted to a corresponding one of thebattery blocks; and a monitor activation device, wherein the battery ECUis configured to wirelessly transmit commands to the voltage monitors,the voltage monitors are configured to detect voltage information of theunit batteries and wirelessly transmit the detected voltage informationto the battery ECU, and the monitor activation device is configured tosequentially activate the voltage monitors with time lags therebetweenin a predetermined order recognized by the battery ECU, wherein thevoltage monitors are further configured to be sequentially activated inthe predetermined order in response to electric power sequentiallysupplied to the voltage monitors in the predetermined order or signalssequentially transmitted to the voltage monitors in the predeterminedorder.
 11. The battery monitoring apparatus as set forth in claim 10,wherein the monitor activation device comprises the battery ECU, andeach of the voltage monitors is connected with the battery ECU viapredetermined wiring.
 12. The battery monitoring apparatus as set forthin claim 11, wherein the predetermined wiring comprises a plurality ofelectric power lines, each of the voltage monitors is connected with thebattery ECU via a corresponding one of the electric power lines, each ofthe voltage monitors is configured to be supplied with electric powerfrom the battery ECU via the corresponding electric power line andthereby activated, and the battery ECU is configured to sequentiallystart the supply of electric power to the voltage monitors in thepredetermined order and thereby sequentially activate the voltagemonitors in the predetermined order.
 13. The battery monitoringapparatus as set forth in claim 11, wherein each of the voltage monitorsis configured to be activated, upon receipt of a predeterminedactivation signal, using electric power supplied from an electric powersource other than the battery ECU, the predetermined wiring comprises aplurality of signal lines that transmit the activation signal, butneither the commands nor the voltage information, each of the voltagemonitors is connected with the battery ECU via a corresponding one ofthe signal lines, and the battery ECU is configured to send theactivation signal, via the corresponding signal lines, sequentially tothe voltage monitors in the predetermined order and thereby sequentiallyactivate the voltage monitors in the predetermined order.
 14. Thebattery monitoring apparatus as set forth in claim 13, wherein for eachof the voltage monitors, the electric power source other than thebattery ECU is the unit batteries of the battery block corresponding tothe voltage monitor.
 15. The battery monitoring apparatus as set forthin claim 11, wherein the monitor activation device further comprises thevoltage monitors, each of the voltage monitors is configured to beactivated, upon receipt of a predetermined activation signal, usingelectric power supplied from an electric power source other than thebattery ECU, the predetermined wiring comprises a signal line thattransmits the activation signal, but neither the commands nor thevoltage information, and a plurality of connection lines that transmitthe activation signal, the battery ECU is connected with a predeterminedone of the voltage monitors via the signal line, all the voltagemonitors are connected, via the connection lines, in series with eachother in the predetermined order from the predetermined voltage monitor,and the battery monitoring apparatus is configured so that: the batteryECU sends the activation signal to the predetermined voltage monitor viathe signal line and thereby activates the predetermined voltage monitor;and then the remaining voltage monitors are sequentially activated inthe predetermined order through successive transmission of theactivation signal from each activated one of the voltage monitors toanother of the voltage monitors which is connected with the activatedvoltage monitor via a corresponding one of the connection lines and hasnot been activated yet.
 16. The battery monitoring apparatus as setforth in claim 15, wherein for each of the voltage monitors, theelectric power source other than the battery ECU is the unit batteriesof the battery block corresponding to the voltage monitor.